Title: Poly (ε-caprolactone) as substrate for water denitrification

Authors: Haihong Zhou, Xuan Zhao, Jianlong Wang

Addresses: Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084, PR China. ' Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084, PR China. ' Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084, PR China

Abstract: In this paper, poly (ε-caprolactone) (PCL) was used as carbon source and biofilm supporter in a fixed bed bioreactor to biologically remove nitrate from drinking water. The experimental results showed that denitrifying microorganisms could easily adapt to PCL as carbon source and attach to the surface of PCL granules. The fine biofilm could form on the surface of PCL granules within 15 days. Denitrification rate was influenced by temperature greatly and it decreased sharply at low temperature (below 20°C) and it was strongly linearly correlated with influent DO level. The denitrification rate at DO 8.5 mg/L was 47.4% of the value at DO 1.4 mg/L. Fixed-bed bioreactor packed with PCL granules could remove 50 mg/L influent nitrate completely, but the effluent DOC and suspended matter level were high. Accordingly, post-treatment unit are needed to ensure the good quality of effluent. Nitrite level did not accumulate in the whole experiment. Microbial growth was the main reason for reactor clog.

Keywords: drinking water; nitrate removal; denitrification; biofilms; fixed bed bioreactors; PCL; microbial growth.

DOI: 10.1504/IJEP.2009.027235

International Journal of Environment and Pollution, 2009 Vol.38 No.3, pp.349 - 359

Published online: 18 Jul 2009 *

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